As a method for jointing electronic parts or the like to connection terminals over a wiring substrate, there has been known in the prior art a method using solder bumps (or protruding electrodes). These solder bumps are usually formed by printing a solder paste on a plurality of connection terminals formed on the printed face of the wiring substrate, with a solder paste printing apparatus, and by melting the solder-printed layers by a re-flow.
The procedure of printing the solder paste on the connection terminals with the solder paste printing apparatus of the prior art is as follows.
At first, the wiring substrate is horizontally held on the upper face of a table or a wiring substrate holder. Next, a solder paste printing plate-shaped mask is arranged over the printed face of the wiring substrate. In this mask, there are arranged a plurality of through holes, which are formed to correspond to the connection terminals. Next, a squeezee is brought into contact with the upper face of the mask and is fed on its forward side with a solder paste. In this state, the squeezee is moved along the upper face of the mask. Then, the through holes are filled with the solder paste by the squeezee so that solder-printed layers are formed on the connection terminals. By finally lowering the table as a whole vertically, the mask is detached from the printed face thereby to disengage the solder-printed layers from the through holes (as referred to JP-A-2002-76600 (Paragraph 0008, FIG. 1(D) etc.) and JP-A-2000-177098 (Paragraph 0018, FIG. 1 etc.), for example).